1. Field of the Invention
This invention relates to a microcomputer and, more particularly, to a microcomputer capable of performing MIN and MAX operations.
2. Description of the Related Art
In fuzzy inferential reasoning and fuzzy control, MIN and MAX operations are often used. There are also instances where operations for fuzzy inferential reasoning and fuzzy control are executed using a device having a special-purpose architecture specifically for fuzzy operations, such as a fuzzy special-purpose coprocessor, IC chip or a read-only memory (ROM). In many applications, however, these operations are executed by a general-purpose binary microcomputer suitably programmed for fuzzy operations.
FIG. 3 illustrates the operation which takes place in a case where a MIN or MAX operation is executed by a general-purpose microcomputer. First, an instruction CMP for comparing source data and destination data is executed, then a conditional branch instruction Bcc conforming to a MIN or MAX operation is executed, and finally a transfer instruction MOVE for the compared data is executed.
Thus, with this method of executing MIN and MAX operations by the software of a general-purpose microcomputer, the three instructions CMP, Bcc and MOVE are necessary and these instructions must be executed in succession. A problem that results is low speed due to a slow-down in operation speed.
A problem encountered with a fuzzy special-purpose coprocessor is high cost, since 600,000 transistors, for example, are required. In addition, a fuzzy special-purpose IC chip or ROM is incapable of executing processing other than the intended fuzzy inferential reasoning. In particular, the rules and membership functions in fuzzy inferences cannot be changed in case of a ROM.